August 5, 2009
01:00 PM (EDT)

News Release Number: STScI-2009-24

Astronomers Find Hyperactive Galaxies in the Early Universe

August 5, 2009: Even some galaxies may have been hyperactive youngsters. Looking almost 11 billion years
into the past, astronomers have measured the motions of stars for the first time in a very distant
galaxy. They are whirling at a speed of one million miles per hour—about twice the speed of our
Sun through the Milky Way. Even stranger, the galaxies are a fraction the size of our Milky Way,
and so may have evolved over billions of years into the full-grown galaxies seen around us today.
Astronomers are puzzled by how galaxies like these formed. They may be what will eventually
become the dense central regions of very large galaxies.

The galaxies were found by using the combined power of NASA’s Hubble Space Telescope and
the 8-meter Gemini South telescope in Chile. Hubble shows that the galaxies are a fraction the size of
most galaxies we see today. The Gemini telescope clocks their speed by using spectroscopy.
To witness the formation of these extreme galaxies astronomers plan to observe galaxies even
farther back in time with Hubble’s new Wide Field Camera 3.